214 SUMMARY OF CURRENT RESEARCHES RELATING TO 



B. INVERTEBRATA. 



Dotted Substance of Leydig.* — Dr. B. Hfiller has a note on the so-called 

 Leydig's dotted substance in the central nervous system ; the simplest con- 

 dition of the central network of higher invertebrates is certainly to be found 

 in some of the lower cephalophorous molluscs, such as the Chitons ; in them 

 the connective-tissue takes no part in the formation of the central plexus, 

 which is exclusively formed of processes of ganglion-cells. 



In the annelids Lepidanthenia eleyans and Nereis costae, the central non- 

 ganglionated portion of the cerebrum consists of a nervous and connective 

 plexus, which is traversed by commissural fibres and larger nerve-fibres ; 

 the inner fibres of the optic nerves arise from the central nervous plexus, 

 while their outer fibres take their origin directly from the overlying larger 

 ganglionic cells. The study of other groups leads the author to conclude 

 that the central plexus is partly nervous and is partly formed by the 

 processes of the ganglionic cells, and that this double mode of origin of the 

 nerves is to be always found; as to the origin of this central nervous 

 system it may be explained as being derived from that primitive system 

 which covered the whole surface of the body. 



Enterochlorophyll and Allied Pigments.! — Dr. C. A. MacMunn brings 

 forward evidence decisive of the animal origin of enterochlorophyll, and of 

 the presence of a true animal chlorophyll in Spongilla ; in Anthea cereus, 

 on the other hand, the chlorophyll is due to symbiotic alg^. The memoir 

 contains also the author's observations on the saponifying of vegetable 

 chlorophyll. 



Myohaematin and the Histohaematins.J — Dr. C. A. MacMunn adduces 

 evidence in favour of the respiratory functions of these pigments, the 

 discovery of which tends to confirm the theory that the formation of 

 carbonic acid and the absorption of oxygen takes place in the tissues and 

 not in the blood. Haematoporphyrin is identical with polyperythrin and is 

 closely related to actinohaematin. 



Micro-organisms in Thermal 'Water.§ — MM. A. Certes and Garrigou 

 have been investigating the question whether there normally exist in thermal 

 waters living organisms, and what part they play in the formation of that 

 " glairine " and " baregine " which is found in sulphuretted waters. They 

 conclude that in water taken at Luchon at a temperature of 64° C. there are 

 rare very transparent mobile small rods, and more rarely immobile filaments, 

 longer than the rods ; in neither of these organisms were any granulations 

 of reduced sulphur to be detected ; no algse, diatoms, or infusoria were to 

 be seen, but the debris of vegetable or animal matter show that the waters 

 are fertilized by atmospheric germs, and lead us to think they may be re- 

 garded as more or less successful culture fluids for such germs as can ac- 

 commodate themselves to darkness, high temperature, and special chemical 

 composition. When the water is not higher than 50° the masses of baregine 

 appear ; these are nothing more then zoogloeae of rods mixed with grains 

 of reduced sulphur. Further experiments are necessary to determine the 

 chemical and biological action of the rods, and this knowledge will throw 

 a light on the therapeutics of mineral waters. 



• Morphol. Jahibncb, xii. (1886) pp. 325-32. 



t Phil. Trans., clxxvii. (1886) pp. '^35-66 (3 charts and 1 pi). 



j Op. cit., pp. 267-96 (1 chart and 1 pi.). 



§ Cumptts Rcndiis, ciii. (1886) pp. 703-6. 



